The invention relates to a turbine ring assembly comprising a plurality of ring sectors made of ceramic matrix composite material together with a ring support structure.
For turbine ring assemblies that are made entirely out of metal, it is necessary to cool all of the elements of the assembly and in particular the turbine ring, which is subjected to the highest temperature streams. This cooling has a significant impact on the performance of the engine, since the cooling stream that is used is taken from the main stream of the engine. In addition, using metal for the turbine ring limits potential for increasing temperature within the turbine, even though that would serve to improve the performance of aeroengines.
In an attempt to solve those problems, proposals have been made for turbine ring sectors to be made out of ceramic matrix composite (CMC) material in order to avoid using a metal material.
CMC materials present good mechanical properties that make them suitable for constituting structural elements, and advantageously they conserve those properties at high temperatures. Using CMC materials advantageously makes it possible to reduce the cooling stream required in operation and thus to increase the performance of turbine engines. Furthermore, using CMC materials advantageously serves to reduce the weight of turbine engines and to reduce the effect of high temperature expansion encountered with metal parts.
Nevertheless, the existing solutions that have already been proposed can involve assembling a CMC ring sector with metal attachment portions of a ring support structure, with the attachment portions being subjected to the hot stream. Consequently, those assembly solutions can continue to require the use of a cooling stream, at least for cooling said attachment portions that are made of metal. In addition, those metal attachment portions are subjected to expansion at high temperature, which can lead to the CMC ring sectors being subjected to mechanical stress and to them being weakened.
Turbine ring assemblies are also disclosed in Documents US 2014/0271145, US 2004/0047726, U.S. Pat. No. 6,435,824, and GB 2 344 140.
There therefore exists a need to improve existing turbine ring assemblies that make use of CMC material in order to further reduce the quantity of cooling gas that is needed.
There also exists a need to improve existing turbine ring assemblies that make use of CMC material in order to reduce the magnitude of the mechanical stresses to which the CMC ring sectors are subjected in operation.